Backup Crew

Flight

Launch from the Baikonur Cosmodrome; landing
with Soyuz 26 capsule 265 km west of
Tselinograd.

The main goal of the mission was to swap
Soyuz craft with the orbiting crew.The
Salyut 6 station required refueling by mid-January
1978, and this was to be accomplished by a new unmanned supply tanker,
Progress. But the tanker had to dock at the aft port where the propellant line
connections were, and Soyuz 26 was
docked there. Mission control was not yet willing to attempt to redock the
Soyuz at the other port, a now-standard practice.
Accordingly, a new crew was sent up on another
Soyuz spacecraft to dock at the forward port, and
depart in the parked Soyuz 26
spacecraft.On January 11, 1978
Soyuz 27 docked without incident at the front port
carrying cosmonauts Oleg
Makarov and Vladimir
Dzhanibekov, who formed the first visiting crew in the
Soviet space station program (or, for that matter, in any space station
program). Vladimir
Dzhanibekov noticed that as he and Oleg
Makarov approached the station in
Soyuz 27, they were slightly off-course, but he
allowed the automatic system to continue and, with 7 meters (23 ft) to go, it
corrected the slight alignment error. To the relief of mission control,
Soyuz 27 successfully docked at the forward port. For
the docking, the first resident crew withdrew to their
Soyuz 26 spacecraft and sealed the
hatch into
Salyut 6 behind them. This was done in the event of a
depressurization emergency associated with the docking of
Soyuz 27. The
Soyuz 27 crew then encountered their first problem - a
balky hatch that opened suddenly and sent Vladimir
Dzhanibekov and Oleg
Makarov tumbling backwards. The
Salyut crew dove into the
Soyuz and hugged their first visitors.There was
also some concern that stresses and vibrations produced when the 7-ton
Soyuz 27 spacecraft contacted the front port might
transmit through
Salyut 6, forcibly uncoupling
Soyuz 26 from the rear port. The
Soyuz 27-Salyut 6-Soyuz
26 combination massed about 33,000 kg and featured seven compartments: two
descent modules, two orbital modules, the transfer compartment, the work
compartment, and the small aft intermediate compartment. The four cosmonauts
conducted many experiments, including Rezonans, which was designed to determine
if resonant frequencies might threaten the structural integrity of the
three-spacecraft combination. The experiment called for the cosmonauts to jump
around
Salyut 6 on command from the TsUP. The guest crew
spent 5 days on
Salyut 6, then returned to Earth in
Soyuz 26, leaving the fresh
Soyuz 27 spacecraft for the
first resident
crew. This was the first of many such spacecraft swaps.The visiting
crew brought supplies such as food, books and letters, equipment and a French
biological experiment called "Cytos", and Vladimir
Dzhanibekov, an electronics expert, inspected the station's
electrical system. On January 13, 1978 the crews performed for the first time
the now-routine exchange of seat liners and centering weights in their
respective
Soyuz craft. The liners are custom molded for each
space traveler, and are needed for launch and landing, and the weights are
needed to ensure a proper center of mass for the returning craft so it does not
undershoot or overshoot the landing target. While the main reason for the
Soyuz swap was to free the aft port for the Progress,
another reason was that extended exposure to space of the vehicle leads to
degradation of its engine and propellant seals.A now-standard experiment
called "Rezonans" was carried out, which tested the stresses of the
multi-spacecraft structure by simply having the cosmonauts jump up and
down.Cosmonauts Vladimir
Dzhanibekov and Oleg
Makarov returned to earth in the
Soyuz 26 spacecraft after spending five days on the
station.

One piece of information that the visiting crew didn't
immediately tell the station crew was that Georgi
Grechko's father had died ten days earlier. Psychologists had
decided such knowledge was not in the best interests of a cosmonaut spending
several months in space. Oleg
Makarov and Vladimir
Dzhanibekov informed
Commander Yuri
Romanenko, however, who assumed the responsibility of telling
Georgi Grechko when they landed. Years later, Georgi
Grechko said in an interview that he also thought the
decision was the right one.

The four cosmonauts conducted many
experiments, including Rezonans, which was designed to determine if resonant
frequencies might threaten the structural integrity of the three spacecraft
combination (Soyuz 26,
Salyut 6 and
Soyuz 27). Additional work were photography of the
Earth surface, solar observation and astronomical experiments.

The
Soyuz spacecraft is composed of three elements
attached end-to-end - the Orbital Module, the Descent Module and the
Instrumentation/Propulsion Module. The crew occupied the central element, the
Descent Module. The other two modules are jettisoned prior to re-entry. They
burn up in the atmosphere, so only the Descent Module returned to
Earth.Having shed two-thirds of its mass, the
Soyuz reached Entry Interface - a point 400,000 feet
(121.9 kilometers) above the Earth, where friction due to the thickening
atmosphere began to heat its outer surfaces. With only 23 minutes left before
it lands on the grassy plains of central Asia, attention in the module turned
to slowing its rate of descent.Eight minutes later, the spacecraft was
streaking through the sky at a rate of 755 feet (230 meters) per second. Before
it touched down, its speed slowed to only 5 feet (1.5 meter) per second, and it
lands at an even lower speed than that. Several onboard features ensure that
the vehicle and crew land safely and in relative comfort.Four parachutes,
deployed 15 minutes before landing, dramatically slowed the vehicle's rate of
descent. Two pilot parachutes were the first to be released, and a drogue chute
attached to the second one followed immediately after. The drogue, measuring 24
square meters (258 square feet) in area, slowed the rate of descent from 755
feet (230 meters) per second to 262 feet (80 meters) per second.The main
parachute was the last to emerge. It is the largest chute, with a surface area
of 10,764 square feet (1,000 square meters). Its harnesses shifted the
vehicle's attitude to a 30-degree angle relative to the ground, dissipating
heat, and then shifted it again to a straight vertical descent prior to
landing.The main chute slowed the
Soyuz to a descent rate of only 24 feet (7.3 meters)
per second, which is still too fast for a comfortable landing. One second
before touchdown, two sets of three small engines on the bottom of the vehicle
fired, slowing the vehicle to soften the landing.